1. Field of the Invention
This invention relates to a grommet, and more particularly to a grommet which enables an elongated member (e.g. a wire harness) to be positively and easily passed through and retained relative to a mounting plate such as a panel of a vehicle body.
2. Description of the Prior Art
There have heretofore been proposed various grommets which enable a wire harness to be passed through and mounted on a panel of a car body of an automobile. The Applicant of the present application has proposed a grommet (Japanese Patent Unexamined Publication No. 8-212857: conventional example) which includes a smaller-diameter tubular portion for fitting on a wire harness, a larger-diameter tubular portion for fitting in a mounting hole, a tapering tubular portion interconnecting the smaller-diameter and larger-diameter tubular portions, and a groove edge portion and holding piece portions which are provided at an outer peripheral surface of the larger-diameter tubular portion.
In this example, the larger-diameter tubular portion is turned inside out, with its inner peripheral surface directed outwardly, and by doing so, the holding piece portions are deformed into a generally tapering, cylindrical shape, and are passed through the mounting hole, and subsequently the smaller-diameter portion is drawn into the mounting hole, and as a result, because of a resilient force tending to restore the holding piece portions into their initial shape, the larger-diameter portion is restored into its initial shape in such a manner that the groove edge portion is engaged in a peripheral edge of the mounting hole. Therefore, the wire harness can be easily and positively mounted with a smaller force.
In the above example, a plurality of tongues, serving as the holding piece portions, extend radially from the outer peripheral surface of the larger-diameter tubular portion. These tongues have a relatively small thickness, and therefore even when the tongues are deformed into a generally tapering (or convergent) cylindrical shape, and then passed through the mounting hole, a sufficient resilient force is not obtained to restore the larger-diameter tubular portion into its initial shape.
Namely, in this grommet, the operator must perform an auxiliary operation to draw the smaller-diameter tubular portion into the mounting hole until the groove portion is brought into fitting engagement in the inner peripheral edge of the mounting hole. In view of this problem, there has been desired an improvement to make the wire harness-mounting operation simpler.